Positive dobby

ABSTRACT

A positive dobby of the Hattersley type comprising a baulk having draw hooks hinged on the ends thereof which are engageable patternlike with back-and-forth movable draw knives, and a pivotable stop beam which tightly presses on the draw hook when in the patternlike lifted normal position and urges same against the stationary bar so that the locking surface of stop beam and draw hook lie, in the engaged condition, between the pivot axis of the draw hook on the baulk and the pivot axis of the stop beam. The stop beam has a drive mechanism for moving same from its position of the tight, playfree engagement with the draw hook when in the lifted normal position to the position of the abutment of one portion of the stop beam on the upper side of the draw hook which is in a not lifted normal position, through which the stop beam becomes also a press-down beam for the draw hooks.

United States Patent [191 Sc'hwarz Dec. 3, 1974 POSITIVE DOBBY [75] Inventor: 4 Rudolf Schwarz, Horgen-Zurich,

Switzerland [73] Assignee: Staubli Ltd., l-lorgen-Zurich,

, Switzerland [22] Filed: Mar. 22, 1973 21] Appl. No.: 343,888

[30] Foreign Application Priority Data Mar. 28, 1972 Switzerland 4627/72 [52] US. Cl. 1139/71, 139/74 [51] Int. Cl. D03c 1/06 [58] Field of Search. 139/66-74 [56] v References Cited UNITED STATES PATENTS 1,546,728 7/1925 Gregson 139/74 3,057,379 10/1962 Staubli.....

3,665,973 5/1972 Reisdorf 139/71 FOREIGN PATENTS OR APPLICATIONS 862,666 3/1961 Great Britain 139/71 886,310 1/1962 Great Britain... 139/74 439,154 12/1967 Switzerland ..139/7l 959,899 3/1957 Germany 139/71 Primary Examiner.lames Kee Chi Attorney, Agent, or Firm-Woodhams, Blanchard and Flynn [57] ABSTRACT A positive dobby of the Hattersley type comprising a baulk having draw hooks hinged on the ends thereof which are engageable patternlike with back-and-forth movable draw knives, and a pivotable stop beam which tightly presses on the draw hook when in the patternlike lifted normal position and urges same against the stationary bar so that the locking surface of stop beam and draw hook lie, in the engaged condition, between the pivot axis of the draw hook on the I baulk and the pivot axis of the stop beam. The stop beam has a drive mechanism for moving same from its position of the tight, playfree engagement with the draw hook when in the lifted normal position to the position of the abutment of one portion of the stop beam on the upper side of the draw hook which is in a not lifted normal position, through which the stop beam becomes also a press-down beam for the draw hooks.

17 Claims, 6 Drawing Figures PATENTELBEB 3,851,675

The invention relates to a positive dobby of the Hattersley type comprisinga baulk having draw hooks hinged on the ends thereof and which are engageable in a patternlike manner by back-and-forth movable draw knives, a swingable stop beam which presses the draw hook longitudinally when in its lifted normal position, clearance-free against the stationary traverse, whereby opposed longitudinally facing locking surfaces on the stop beam and the draw hook lie, in their engaged condition, between the pivot axis of the draw hook on the baulk and the pivot axis of the stop beam.

By the swinging movement, the draw hook is to be pressed from the lifted position into the carry-along position for the draw knives.

In these machines, the stop beams extend over the entire width of the machine and move with the draw hook being lifted and in the normal position against the longitudinally facing support surfaces of the draw hooks in order to hold the draw hooks longitudinally tightly against a stationary bar. This is done either by a linear movement toward the locking surface or by a downward swinging toward thelifted draw hook. The stop beams move automatically.

The faster a machine operates, the shorter and safer and therewith also more automatic the movements of the individual parts must be carried out. The lowering of the draw hooks from their lifted normal position by means of the dead weight, which is known, so far is no longer sufficient. One started to permit a separate power component to act on the hooks, which power component presses down all hooks together into the joining position from where they are individually controlled. Subsequently, they are again lifted. A further suggestion is to provide a spring for each draw hook to speed up the falling down thereof.

The springs and transversely positioned beams are not sufficient with respect to the available room, the

magnitude of the force, the spring deflection here particularly at the end of the path of movement with respect to an assurance of synchronized operation.

The purpose of the invention is to provide a device which assures a quick and synchronized sequence of movement, whereby the lifted draw hooks are held tightly and the draw hooks, which must be lowered in a patternlike manner, are lowered positively.

The purpose is attained in the said positive dobby by providing, according to the invention, the stop beam with a drive mechanism for at least one path of swing from its position of tight, playfree engagement with the draw hook,'when in' the liftednormal position, to a position of abutment of one portion of this stop beam on the upper side of the draw hook as the latter moves toward a lowered normal position, through which the stop beam becomes also the press-down member for the draw hooks. v

This arrangement makes it possible to both hold the draw hook in a lifted position clearancefree and also to lower same frictionally on the draw knives with only one pivotal member per draw hook row or per draw hook, and to form, at the same time, the clearance which is necessary for the control operation.

In an advantageous embodiment, the stop beam can be divided into as many individual levers as the dobby has bau'lks or draw hooks and each lever has in at least one direction of movement one individual drive mechanism. Through this, an individual control of the draw hooks is made possible, that is a control which permits a repeated release of a draw hook in the controlled upper position. Thus, each hook will have a lever with a stationary pivot axis and beloaded by a spring associated therewith. The lever and spring will accelerate the draw hook toward the draw knife and delay same in the reversed direction of movement. Thus, the oppositely directed support surfaces move away from one another during a pivoting of the lever and the hook and meet again in such a manner that in the second case, the clearance is totally eliminated and, in the first case, the end of the lever will swing out of the way of the path of any hook part, at the same time forming the clearance between this end and the support surface of the draw hook.

In dobbies, in which during the normal position of the knife all hooks are brought, through a collective member (for example, a raising rail) to the draw knife, the individual levers are driven positively in one direction by a rail which extends transversely over a row of draw hooks and in the other direction by springs, whereby the support projection of the rail is provided in one type of construction outside and in a different type of construction inside of a path of any part of the draw hook.

Three exemplary embodiments of the subject matter of the invention are illustrated in the drawings, in which:

FIG. 1 is a schematic side view of a portion of a double-lift positive dobby which is mounted on a loom,

FIG. 2 illustrates in anenlarged scale the arrangement of the shed-forming parts of adobby of the Hattersley type and a first exemplary embodiment of the invention,

FIG. 3 illustrates a draw hook of asecond modified embodiment of a stop and press down lever and FIG. 4 is the associated front view of the draw hook row and the drive elements, both for individual and also for total drive,

FIG. 5 illustrates a draw hook of a third modified embodiment of a stop and press down lever, and

FIG. 6 is the associated front view of the draw hook row.

According to FIG. 1, the loom frame 1 supports the heddle frames 2 for vertical movement and the dobby 3. The dobby 3 has a shed-forming device of the Hattersley type (see also FIG. 2) having a baulk 4 with two draw hooks 5, 50 hinged to its ends, per heddle frame. The draw knives 6, 60 are used to draw out the draw hooks, while the draw hooks, in their lifted normal position, are held tightly against the stationary stops 8, 80 by the movable stop knives 7, 70. The numeral 9 identilies the rocking lever and the transmission elements between the dobby and the heddle frame.

According to FIG. 2, the stop and'press down lever '7 or is mounted on-a shaft 57 and extends over all draw hooks 5 or 50. Each of the levers 7 or 70 have an arm 77 thereon, the movement of which is controlled by the movable stops 20A. In the upper draw hook row, the draw hook 5- is illustrated in the lifted normal position and in the lower draw hook row, the draw hook 50 is illustrated in the lowered normal position and is ready to be carried along by the draw knife 60. In the lifted position, the locking surface 35 of the beam 7 engages the locking surface 65 of the draw hook 5. Both tion corresponding to the lower row of the draw hooks 50. The beam 70 slides thereby off onto the planar surface 34, which planar surface 34 is initially parallel to the straight line I and extends from the locking surface 65 of the draw hook on the side facing the beam 7. The locking surfaces 35, 65 can be angled or can be lightly curved a few degrees (a) for example 4 from a line perpendicular to the straight line I which is equivalent to an inclination a to the tangent to the .arcuate path of the locking surface 65 of the draw hook 5, whereby the locking surfaces project from the tangential surface II toward the draw knife 6. They can also be positioned perpendicularly on the connecting straight line between the pivot axis of the draw hook 5 with the baulk 4 on one side and the pivot axis 57 of the beam 7 on the other side.

In place of one through-going beam 7, individual levers 7, 77 can be arranged per draw hook. Prior to the drawing-out movement of" the draw knife 60, the beam 70 must be swung back because otherwise the locking follows immediately the movement of the needle 10. One thereby obtains the position of needle 10, draw hook 5 and lever 7, 77 illustrated in dashed lines. Before the draw knife 6 draws out the draw hook 5 to the .left, the rail 22 must, through its movement to the left,

. cause the lever 7, 77 to swing back into the position illustrated by dashes. If this would not be the case, the

draw hook would not be able to slide beneath the stop surfaces 35, 65'would again engage. Aside from the movable stop 20A of FIG. 2, control of arms 77 can, as shown in the further described modified embodiments, be supplemented in part by springs.

For the exemplary discussion on. the further examples of the invention, reference is made in the drawing and in the following description only to the upper draw hook of the shed-forming device, or rather to the row of side-by-side arranged upper draw hooks. Said draw hook 5 is hinged to the not illustrated baulk at in FIG. 3. The draw knife 6 is used to draw out the draw hook in the usual manner. The patternlike control is performed by the needle 10. y

In the second exemplary embodiment according to FIGS. 3 and 4, one, stop and press down lever 7, 77 is arrangedfor each draw hook 5 along the entire cross shaft 57. The lever has two arms, 7 and 77, whereby the I free end 25 of the arm 7 is rounded to form a roller-like stop point which cooperates with the also rounded locking-surface 55 on the draw hook 5. The other arm 77 extendsinto the space between the fixed stop bar 20 and a movable rail 22. A tension spring 23 is clamped to and extends between the arm 77 and the rail 22.

If the draw hook 5 is supposed to remain in the position illustrated in solid lines in FIG. 3, that is in a lifted position and under the control of the needle 10, then the stop point 25 of the arm 7 remains also in engagement with the locking surface 55. The clearance between lever 7, 77 and draw hook 5 is eliminated. Also a back-and-forth movement of the rail 22 does not affect the position of the parts.

To control the draw hook into the lowered position, that is into the position illustrated by dashes, the needle 10 is lowered by the control system which is conventional and not shown. Under the effect of the force of the spring 23, the lever 7, 77 swings and adds to the gravitational force which already acts on the draw hook 5. The stop point 25 of the arm 7 slides thereby off on the plane 24 of the draw hook 5. Thus, the draw hook point 25. In this arrangement, there exists the advantage of an individual control of the draw hooks, however, the disadvantage of a possible uncertainty with respect to the synchronized movement of draw knife 6 and rail 22.

The disadvantage of such uncertainty has been eliminated in the third exemplary embodiment according to FIGS. 5 and 6. The end of the arm 7 is divided into two parts, namely the stop 25 and the finger 26. The stop 25 is constructed in the same manner as in the second above-mentioned exemplary embodiment and cooperates also with the locking surface of the draw hook 5 for the purpose of canceling the clearance between the engaging parts and holding the draw hook in the lifted normal position.

The finger 26, however, engages the upper edge surface 27 of the draw hook and serves to press down the draw hook 5 when same is lowered. The radius of swing of said finger 26 is greater than the radius of swing of the stop 25. This makes it possible that the locking surface 55 of the draw hook 5 is released from and moves beneath the stop 25 in direction of the arrow a during the drawing out movement by the draw knife 6. Thus the lever 7, 77 need not be swung back prior to the movement of the draw knife 6. A draw hook 5 which is moved upwardly by a needle 10 from the lowered (illustrated in dashes) to the lifted (illustrated in full lines) position will press the lever 7, 77 against the action of the spring 23, at the beginning through the finger 26 and later through the stop 25 into the end position. During this-movement, the curved plane of the locking surface 55 of the draw hook 5 gradually meets the stop 25 of the lever 7, 77 until between these two, according to an aspect of the invention, and measured inthe longitudinal direction, clearance 'or play ,no longer exists. The lever 7, 77 has thus taken over the functioning of a stop knife. If one wants to reduce the work which the needle 10 must carry out during a lifting of a draw hook 5, the rail 22 can be moved back and forth, which movement swings back the lever 7, 7.7. It isimportantthat the lever 7, 77 is released after the swinging back movement, before the draw hook 5 starts to move into its lifted position. Thus, the stop 25 of the arm 7 engages the locking surface 55 and the clearancetherebetween is cancelled. It is advantageous to choose the relative positions of the stop 25 and the finger 26 in such a manner that in the case of a totally lifted draw hook 5, the finger 26 does not contact the the associated drive mechanism 30, 32, 33, 36 for the swinging movements of the lever 7, 77 in both directions'andon the left side thereof an embodiment with a beam 7 which extends over all draw hooks 5 of one row for locking and pressing down the draw hooks. The drive mechanisms are thereby arranged laterally.

The tension spring 23 (HO 4) is used to swing the lever downwardly from the locking position. The swinging back movement is performed by a crank lever 32 which is swingably supported on a shaft 30. The rail 22 is secured'at one end of the crank lever, while the other endcarries a roller 33 which rolls off on a cam plate 36 of the drive shaft. This mechanism serves the drive of the back-and-forth (into and out of the drawing pagev for FIG. 4) movement of the rail 22 in FIGS. 3 and 5 or stop A in FIG. 2.

The roller-shaped end can engage the pocket 55 during the upward swinging of the draw hook 5 in such a manner that the draw hook is lifted higher than would be effected merely by the control needle 10. The control needle is therewith completely relieved and can be controlled into a different ready position for the next pick from the needle work.

Although a particular preferred embodiment of the invention has been'disclosed above for illustrative purposes, it will be understood that variations or modifications thereof which lie within the scope of the appended claims are fully contemplated.

The embodiments of the invention in which exclusive property or privilege is claimed are defined as follows:

1. A positive dobby of the Hattersley type, comprising:

a baulk;

draw hooks extending from and pivoted on the ends of said baulk for patterned movement, said draw hook having a normal, lifted position and a further, lower position;

draw knives mounted for back-and-forth movement beneath corresponding draw hooks and engageable with corresponding lowered draw hooks;

a stationary member engageable by the pivoted end of said draw hooks;

pivotable stop means extending toward and overlying said draw hook and in one position thereof tightly longitudinally pressing against said draw hook in the normal lifted position of the latter for longitudinally urging said draw hook against said stationary member, wherein longitudinally opposed locking surfaces of said stop means and draw hook abut in a tight, play-free manner at a location between the pivot axisjoining said draw hook to said baulk-and the pivot axis of said stop means, said stop means including a portion thereof positively engageable with the upper side of said draw hook for pushing transversely thereon;

drive means adapted to urge said pivotable stop means out of said one position in .a directiontoward said draw hook for positively pushing said draw hook toward its further, lower position.

2. A positive dobby according to claim 1 in which said locking surface of said draw hook faces substantially laterally away from said baulk and toward said pivotable stop means pivot in said normal lifted position, said stop means comprises a rigid arm extending longitudinally from said stop means pivot, said portion being a lower surface of said rigid arm adjacent the free end thereof, said upper side of said draw hook including a substantially planar surface extending from said draw hook locking surface for positive longitudinal sliding engagement by said arm surface during lowering of said draw hook toward said further, lower position.

3. A positive dobby according to claim 1, wherein said pivotable stop means comprises as many individual levers as there are adjacent draw hooks, and said drive means comprises, at least for lever movement in one direction, one individual drive mechanism for each lever.

4. A positive dobby according to claim 1, wherein said drive means comprises one resilient element engaging the pivotable stop means of a given draw hook, and means locating said element for urging said stop means toward the corresponding draw knife.

5. A positive dobby according to claim 4, wherein said resilient element is.a tension spring, one end of which connects to said pivotable stop means, said locating means carrying the other end of said spring.

6. A positive dobby according to claim 1, including a movable rail having a path of movement in which a part of said pivotable stop means is located for returning said pivotable stop means upwardly to said one position prior to drawing out of the associated draw hook by the corresponding draw knife.

7. A positive dobby according to claim 1, wherein said locking surface of said pivotable stop means is an edge thereof, said edge and said locking surface of said draw hook having corresponding circular cross sections. 8. A positive dobby according to claim 7, wherein said circular cross section surface of said draw hook terminates in a plane surface on the upper draw hook side and facing said pivotable stop means, said stop means portion being at said edge and being slidable on said plane surface during pivotal movement of said stop means.

9. A positive dobby according to claim 7, wherein said edge of said pivotable stop means is divided into two parts, the ends of said two parts both being substantially circular in cross-section. I

10. A positive dobby according to claim 9, wherein one said part end coacts with said locking surfaceon said draw hook and extends a shorter distance from said stop means pivot than does the other said part end, said circular cross section locking surface on said draw hook gripping only partially around said one part end in such manner that the lowered draw hook can be drawn out beneath said stop means, said other part end of said stop means being engageable with said draw hook on a substantially planar surface of the latter,

11. A positive dobby according to claim 1, in which said opposed locking surfaces of said stop means and draw hook are planar, said planar surfaces when engaged, namely in said lifted position of said draw hook, being slightly angled from a perpendicular to'a straight line extending therethrough from the pivot axis of said draw hook on said baulkadjacent the pivot axis of said stop means.

12. A positive dobby according to claim 11, wherein said planar surfaces are substantially perpendicular to a further line which. extends through the pivot axis of said pivotable stop means and through the pivot axis of said draw hook on said baulk.

13. A positive dobby according to claim 11, wherein said locking surface of said draw hook terminates on the side thereof facing said stop means in a plane which extends substantially parallel to said straight line.

14. A positive dobby according to claim 1, including a control needle for lifting said draw hook toward said normal lifted position and wherein said drive means includes means for pivoting said stop means upwardly, said locking surfaces being so located on said pivotable stop means and draw hook as to interengage during said upward pivoting of said stop means for lifting said draw hook off the fully lifted control needle.

15. A positive dobby according to claim 11, wherein said locking surfaces of said draw hook and stop means are inclined up to 4 to the tangential surface of the curve of pivotal movement of said stop means and with respect to said locking surface of said draw hook, whereby said locking surfaces project from said tangential surface toward said draw knife.

16. A positive dobby according to claim 1 in which said pivotable stop means includes first and second rigidly connected arms extending divergently from the stop means .pivot axis, said stop means engaging said draw hook through the laterally extending one of said arms, the other of said arms engaging said drive means remotely from said pivot axis.

17. A positive dobby according to claim 16 in which said drive means comprises a rail shiftable toward and away from said second arm transversely of the latter, said rail having first end means adjacent said second arm and engageable therewith for positively pivotally returning said first stop means arm upwardly toward said one position after lowering of said draw hook and at least prior to full return of said draw hook to its lifted normal position, said drive means furtherincluding a resilient tension means connected between said second arm and a portion of said rail remote therefrom and responsive to shifting of said rail away from said second arm for pivoting said first arm positively against said draw hook upper side so as to carry out said positive pushing of said draw hook toward its lowered position. i i 

1. A positive dobby of the Hattersley type, comprising: a baulk; draw hooks extending from and pivoted on the ends of said baulk for patterned movement, said draw hook having a normal, lifted position and a further, lower position; draw knives mounted for back-and-forth movement beneath corresponding draw hooks and engageable with corresponding lowered draw hooks; a stationary member engageable by the pivoted end of said draw hooks; pivotable stop means extending toward and overlying said draw hook and in one position thereof tightly longitudinally pressing against said draw hook in the normal lifted position of the latter for longitudinally urging said draw hook against said stationary member, wherein longitudinally opposed locking surfaces of said stop means and draw hook abut in a tight, play-free manner at a location between the pivot axis joining said draw hook to said baulk and the pivot axis of said stop means, said stop means including a portion thereof positively engageable with the upper side of said draw hook for pushing transversely thereon; drive means adapted to urge said pivotable stop means out of said one position in a direction toward said draw hook for positively pushing said draw hook toward its further, lower position.
 2. A positive dobby according to claim 1 in which said locking surface of said draw hook faces substantially laterally away from said baulk and toward said pivotable stop means pivot in said normal lifted position, said stop means comprises a rigid arm extending longitudinally from said stop means pivot, said portion being a lower surface of said rigid arm adjacent the free end thereof, said upper side of said draw hook including a substantially planar surface extending from said draw hook locking surface for positive longitudinal sliding engagement by said arm surface during lowering of said draw hook toward said further, lower position.
 3. A positive dobby according to claim 1, wherein said pivotable stop means comprises as many individual levers as there are adjacent draw hooks, and said drive means comprises, at least for lever movement in one direction, one individual drive mechanism for each lever.
 4. A positive dobby according to claim 1, wherein said drive means comprises one resilient element engaging the pivotable stop means of a given draw hook, and means locating said element for urging said stop means toward the corresponding draw knife.
 5. A positive dobby according to claim 4, wherein said resilient element is a tension spring, one end of which connects to said pivotable stop means, said locating means carrying the other end of said spring.
 6. A positive dobby according to claim 1, including a movable rail having a path of movement in which a part of said pivotable stop means is located for returning said pivotable stop means upwardly to said one position prior to drawing out of the associated draw hook by the corresponding draw knife.
 7. A positive dobby according to claim 1, wherein said locking surface of said pivotable stop means is an edge thereof, said edge and said locking surface of said draw hook having corresponding circular cross sections.
 8. A positive dobby according to claim 7, wherein said circular cross section surface of said draw hook terminates in a plane surface on the upper draw hook side and facing said pivotable stop means, said stop means portion being at said edge and being slidable on said plane surface during pivotal movement of said stop means.
 9. A positive dobby according to claim 7, wherein said edge of said pivotable stop means is divided into two parts, the ends of said two parts both being substantially circular in cross-section.
 10. A positive dobby according to claim 9, wherein one said part end coacts with said locking surface on said draw hook and extends a shorter distance from said stop means pivot than does the other said part end, said circular cross section locking surface on said draw hook gripping only partially around said one part end in such manner that the lowered draw hook can be drawn out beneath said stop means, said other part end of said stop means being engageable with said draw hook on a substantially planar surface of the latter.
 11. A positive dobby according to claim 1, in which said opposed locking surfaces of said stop means and draw hook are planar, said planar surfaces when engaged, namely in said lifted position of said draw hook, being slightly angled from a perpendicular to a straight line extending therethrough from the pivot axis of said draw hook on said baulk adjacent the pivot axis of said stop means.
 12. A positive dobby according to claim 11, wherein said planar surfaces are substantially perpendicular to a further line which extends through the pivot axis of said pivotable stop means and through the pivot axis of said draw hook on said baulk.
 13. A positive dobby according to claim 11, wherein said locking surface of said draw hook terminates on the side thereof facing said stop means in a plane which extends substantially parallel to said straight line.
 14. A positive dobby according to claim 1, including a control needle for lifting said draw hook toward said normal lifted position and wherein said drive means includes means for pivoting said stop means upwardly, said locking surfaces being so located on said pivotable stop means and draw hook as to interengage during said upward pivoting of said stop means for lifting said draw hook off the fully lifted control needle.
 15. A positive dobby according to claim 11, wherein said locking surfaces of said draw hook and stop means are inclined up to 4* to the tangential surface of the curve of pivotal movement of said stop means and with respect to said locking surface of said draw hook, whereby said locking surfaces project from said tangential surface toward said draw knife.
 16. A positive dobby according to claim 1 in which said pivotable stop means includes first and second rigidly connected arms extending divergently from the stop means pivot axis, said stop means engaging said draw hook through the laterally extending one of said arms, the other of said arms engaging said drive means remotely from said pivot axis.
 17. A positive dobby according to claim 16 in which said drive means comprises a rail shiftable toward and away from said second arm transversely of the latter, said rail having first end means adjacent said second arm and engageable therewith for positively pivotally returning said first stop means arm upwardly toward said one position after lowering of said draw hook and at least prior to full return of said draw hook to its lifted normal position, said drive means further including a resilient tension means connected between said second arm and a portion of said rail remote therefrom and responsive to shifting of said rail away from said second arm for pivoting said first arm positively against said draw hook upper side so as to carry out said positive pushing of said draw hook toward its lowered position. 